It has been proposed heretofore to use printed circuit windings in permanent magnet type DC motors. One patent which discloses a printed circuit armature for such a motor is U.S. Pat. No. 3,144,574 granted Aug. 11, 1964 to J. Henry-Baudot. The permanent magnet type DC motor described in this patent uses a permanent magnet structure as its stator and as its rotor a printed circuit armature with brushes to energize the winding. However, there are two problems associated with this configuration namely brush wear and electromagnetic radiation from the brush contact. Another alternative would be to maintain the printed circuit windings stationary, and to use the permanent magnet structure as a rotor. The magnetic return plate which must be located on the opposite side of the printed circuit winding could then be held stationary to permit access to the outer periphery of the printed circuit windings where the connections are available for supplying energization current. Unfortunately, the rotation of the permanent magnet structure with its poles adjacent to the magnetic return plate, induces eddy currents in the stationary magnetic return plate, and these eddy currents create substantial losses in the system. These losses may be reduced significantly through the use of laminated magnetic structures; however, this lamination makes the structure somewhat expensive, and losses are still present in the arrangement.
Accordingly, a principal object of the present invention is to provide an improved low loss brushless DC motor. A collateral object of the invention is to reduce the size of rigid disk digital memory systems.